揮發性有機物質 ( VOCs ) 在環境中有許多不同層面的影響，因此在空氣中的定性、定量是評估VOCs問題的基本工作。可靠的濃度校正往往建構在標準氣體的使用，利用標準氣體穿插於連續量測過程的方法，稱之為外標校正 ( external calibration ) ，而內標校正 ( internal calibration ) 則是將標準品添加於樣品內，與樣品一同進入量測儀器。而作為良好的標準品必須具備化學成分輸出穩定的特性。市面上除了使用鋼瓶封裝的揮發性有機化合物，也有部分實驗室選擇使用市售的滲透管作為外標準品的來源，而對於高極性與高反應性物種的配製，使用動態的滲透管法配製較靜態的高壓鋼瓶來得恰當，然而此兩種方式價格均昂貴，且並不能保證長期的穩定性，故本研究擬開發一套成本低廉且製作方法簡便的滲透管外標法，並以內標準法驗證其可靠度，作為未來空氣中VOCs自動量測的線上校正方法。
　　本實驗建構一套能同時量測空氣中VOCs與氟氯碳化物 ( CFCs ) 的分析量測系統，模擬即時量測的情況，對鋼瓶內壓縮空氣進行連續監測，並於監測期間穿插市售標準品與自製滲透管樣品，以火焰離子偵測器 ( FID ) 偵測VOCs，電子捕捉偵測器 ( ECD ) 測量大氣中的CFC-113 ( CCl2FCClF2 ) ；由於CFC-113具有穩定存在於大氣中的特性，在此將其作為本系統的 「 原生內標 」 ，隨著VOCs一起被捕捉進樣，檢視連續量測期間內自製滲透管物質是否和內、外標維持一定比值，希冀藉由市售標準品與大氣中的原生內標CFC-113一同佐證自製滲透管作為線上校正方法的可能性。
　　本論文分為三階段實驗，第一階段使用原生內標CFC-113初步證明自製滲透管的輸出穩定性，CFC-113與自製滲透管的RSD值皆在4 % 內，兩者的感度相對變化皆在 ± 11 % 內；第二階段除了CFC-113之外，再額外加入VOCs混合標準氣體，藉由內、外標來體現自製滲透管作為外標的可行性，由結果顯示三者的RSD值皆在1.5 % 內，且感度相對變化落在 ± 5 %；由第二階段證明自製滲透管具有長時間穩定輸出的能力，具備作為外標的資格後，第三階段將其作為唯一的外標來源，搭配原生內標CFC-113於本校實地模擬野外測站之量測情景，將自製滲透管作為儀器系統偏移與量測物種濃度判斷之依據，自製滲透管與CFC-113在此次實地量測之RSD值均在2.5 %，感度相對變化皆在 ± 6 %，相較於內、外標的穩定，大氣中VOCs濃度跳動較為明顯，以Pentane為例，濃度範圍從0.1到4 ppbv，RSD值為82.0 %，感度相對變化為704 %。
　　本論文證明開發自製滲透管作為外標，提供線上校正的方法具有可行性，與市售標準品相比，除成本低之餘也具備可攜性，大幅降低了野外量測的不便度，未來本實驗室也將朝著填製反應性、極性較高等鋼瓶保存期限低的物種，以落實自製滲透管的使用價值。

Atmospheric volatile organic compounds (VOCs) are complex in composition and variable in abundance. To accurately assess their presence is qualitatively and quantitatively challenging. The reliable calibration of VOC concentrations often depends on the availability of robust standard gas mixtures. They are either analyzed by inserting in between sample aliquots in a continuous measurement process called external standardization, or blended into each sample aliquot called internal standardization. For both types of standardization, the gas mixtures must show high chemical stability overtime. For polar or reactive compounds, dynamic permeation method is preferred to static high pressure cylinders as the stable standard source. However, both types of standards are costly and the long-term stability cannot be ensured. As a result, this study attempted to develop a low-cost and simple external calibration method with self-made permeation tubes and a delivering system. Internal standardization employing a group of airborne compounds persistently existing in the atmosphere – chlorofluorocarbons (CFCs) – was also adopted for validating permeation tubes.
In this study, we set up a heart-cut gas chromatographic system that can measure VOCs and CFCs simultaneously, by flame ionization detection (FID) and electron capture detection (ECD), respectively. The homogeneity of CCl2FCClF2 (CFC-113) in this study was used as an “intrinsic” internal standard to facilitate the validation of our self-made permeation tubes used for external standardization.
The structure of this investigation was divided into three stages. At the first stage, we used atmospheric CFC-113 to validate the stability of the self-made permeation tubes. Both of them were smaller than 4% for the relative standard deviation (RSD), and the relative variations were less than 11%. At the second stage, both CFC-113 (internal standard) and a commercial VOC standard mixture (external standard) were used to assess the stability of the self-made permeation tubes. The results showed that the RSD for CFC-113, the VOC standard mixture, and permeation tubes was less than 1.5%, and the relative variations were less than 5%. Their comparable stability thus validated the self-made permeation method as an external standard source. At the last stage, selected VOCs in outdoor air were targeted continuously, for which the permeation method was the only source of external standardization for the two purposes of concentration calibration and system’s drift check. The RSD for permeation tubes and CFC-113 was less than 2.5%, and the relative variations were less than 6%. In contrast, the variability of VOCs in outdoor air was far more dramatic than that of CFC-113 and permeation tubes. For example, pentane in outdoor air varied between 0.1 and 4 ppbv, with an RSD of 82.0% and relative variation of 704%.
Our results suggested that the self-made permeation tubes can be easily made and adopted as a stable calibration source. The light weight, simplicity, and low cost make this method highly desirable in field and lab applications. Future studies will include more polar and reactive VOCs to further broaden its applicability.

1. Pacifico, F.; Harrison, S. P.; Jones, C. D.; Sitch, S., Isoprene emissions and climate. Atmospheric Environment 2009, 43, 39, 6121-6135.
2. Chang, C.-C.; Wang, J.-L.; Liu, S.-C.; Candice Lung, S.-C., Assessment of vehicular and non-vehicular contributions to hydrocarbons using exclusive vehicular indicators. Atmospheric Environment 2006, 40, 33, 6349-6361.
3. Placet, M.; Mann, C. O.; Gilbert, R. O.; Niefer, M. J., Emissions of ozone precursors from stationary sources:: a critical review. Atmospheric Environment 2000, 34, 12-14, 2183-2204.
4. Baird, C. C., Michael, Environmental Chemistry, 4th Edition. W. H. Freeman: 2005.
5. Bowman, F. M.; Seinfeld, J. H., Ozone productivity of atmospheric organics. J. Geophys. Res. 1994, 99, D3, 5309-5324.
6. Carter, W. P. L., Development of ozone reactivity scales for volative organic compounds. Journal of the Air and Waste Management Association 1994, 44, 881-899.
7. Nakashima, Y.; Kamei, N.; Kobayashi, S.; Kajii, Y., Total OH reactivity and VOC analyses for gasoline vehicular exhaust with a chassis dynamometer. Atmospheric Environment 2010, 44, 4, 468-475.
8. http://www.epa.gov/.
9. 行政院環境保護署, 九十六及九十七年度光化學評估監測站操作品保例行性計畫. 2008.
10. http://www.epa.gov.tw/.
11. Douglas, A. Skoog; F. J. H., Timothy A. Nieman., Principles of Instraumental Analysis, 5th Edition. 1998.
12. Marshall, T. L.; Chaffin, C. T.; Hammaker, R. M.; Fateley, W. G., An introduction to open-path FT-IR atmospheric monitoring. Environmental Science & Technology 1994, 28, 5, 224A-232A.
13. Levine, M. S. H. X. S. P., Optical remote sensing for air pollutants-review. American Industrial Hygiene Association Journal 1994, 55, 10, 953-965.
14. http://vsip.tycg.gov.tw/
15. http://www.nasa.gov/home/index.html.
16. USEPA, Compendium Method TO-14A: The determination of volatile organic compounds ( VOCs) in ambient air using specially prepared canisters with subsequent analysis by gas chromatography.
17. USEPA, Compendium Method TO-15: The determination of volatile organic compounds ( VOCs ) in air collected in specially-prepared canisters and analyzed by gas chromatography/mass spectrometry ( GC/MS )
18. USEPA, Compendium Method TO-17: Determination of volatile organic compounds in ambient air using active sampling onto sorbent tubes.
19. http://www.niea.gov.tw/.
20. Tong, H. Y.; Karasek, F. W., Flame ionization detector response factors for compound classes in quantitative analysis of complex organic mixtures. Analytical Chemistry 1984, 56, 12, 2124-2128.
21. Standardization, I. O. f., ISO Guide 35:Reference materials-General and statistical principles for certification. 2006.
22. http://www.kin-tek.com/articles.html.
23. 金美蘭，趙建南, 標準氣體及其應用. 化學工業出版社: 2003.
24. Switzerland, I. O. f., ISO Guide 99:International vocabulary of basic and general terms in metrology. 1993.
25. Rhoderick, G. C., Development of a gas standard reference material containing eighteen volatile organic compounds. Fresenius'' Journal of Analytical Chemistry 1991, 341, 524-531.
26. Barratt, R. S., The preparation of standard gas mixtures. A review. Analyst 1981, 106, 817 - 849.
27. Rhoderick, G. C.; Zielinski, W. L., Preparation of accurate multicomponent gas standards of volatile toxic organic compounds in the low-parts-per-billion range. Analytical Chemistry 1988, 60, 22, 2454-2460.
28. Rhoderick, G. C.; Yen, J. H., Development of a NIST standard reference material containing thirty volatile organic compounds at 5 nmol/mol in nitrogen. Analytical Chemistry 2006, 78, 9, 3125-3132.
29. Schmidt, W. P.; Rook, H. L., Preparation of gas cylinder standards for the measurement of trace levels of benzene and tetrachloroethylene. Analytical Chemistry 1983, 55, 2, 290-294.
30. http://www.nist.gov/cstl/analytical/gas/ntrm.cfm.
31. Wang, J.-L.; Lin, W.-C.; Chen, T.-Y., Using atmospheric CCl4 as an internal reference in gas standard preparation. Atmospheric Environment 2000, 34, 25, 4393-4398.
32. Goldan, P. D.; Kuster, W. C.; Albritton, D. L., A dynamic dilution system for the production of sub-ppb concentrations of reactive and labile species. Atmospheric Environment (1967) 1986, 20, 6, 1203-1209.
33. Altshuller, A. P.; Cohen, I. R., Application of diffusion cells to production of known concentration of gaseous hydrocarbons. Analytical Chemistry 1960, 32, 7, 802-810.
34. O''Keeffe, A. E.; Ortman, G. C., Primary standards for trace gas analysis. Analytical Chemistry 1966, 38, 6, 760-763.
35. Saltzman, B. E., Standardization of methods for measurement of air pollutants. Journal of the Air Pollution Control Association 1968, 18, 326-329.
36. O''Keeffe, A. E.; Ortman, G. C., Precision picogram dispenser for volatile substances. Analytical Chemistry 1967, 39, 8, 1047-1047.
37. Ho, J. S.-Y.; Schlecht, P. C., Permeation characteristics of organic vapors in silicone rubber tubing. American Industrial Hygiene Association Journal 1981, 42, 1, 70-76.
38. Namiesnik, J., Generation of standard gaseous mixtures. Journal of Chromatography A 1984, 300, 79-108.
39. Mitchell, G. D., A review of permeation tubes and permeator. Separation and Purification Methods 2000, 29, 1, 119 - 128.
40. Chung, C.-W.; Morandi, M. T.; Stock, T. H.; Afshar, M., Evaluation of a passive sampler for volatile organic compounds at ppb concentrations, varying temperatures, and humidities with 24-h exposures. Environmental Science & Technology 1999, 33, 20, 3666-3671.
41. Lucero, D. P., Performance characteristics of permeation tubes. Analytical Chemistry 1971, 43, 13, 1744-1749.
42. Takashi Ibusuki; Fumitoshi Toyokawa; Kazunari Imagami, The performance characteristics of a permeation membrane device for the preparation of dilute standard gas mixtures. Bulletin of the Chemical Society of Japan 1979, 52, 7, 2105-2109.
43. Purdue, L. J.; Thompson, R. J., Rapid, sensitive method for calibration of permeation devices. Analytical Chemistry 1972, 44, 6, 1034-1036.
44. Maria, P.-C.; Gal, J.-F.; Balza, M.; Pere-Trepat, E.; Tumbiolo, S.; Couret, J.-M., Using thermogravimetry for weight loss monitoring of permeation tubes used for generation of trace concentration gas standards. Analytical Chemistry 2002, 74, 1, 305-307.
45. Scaringelli, F. P.; O''Keeffe, A. E.; Rosenberg, E.; Bell, J. P., Preparation of known concentrations of gases and vapors with permeation devices calibrated gravimetrically. Analytical Chemistry 1970, 42, 8, 871-876.
46. Saltzman, B. E.; Feldmann, C. R.; O''Keeffe, A. E., Volumetric calibration of permeation tubes. Environmental Science & Technology 1969, 3, 12, 1275-1279.
47. Saltzman, B. E.; Burg, W. R.; Ramaswamy, G., Performance of permeation tubes as standard gas sources. Environmental Science & Technology 1971, 5, 11, 1121-1128.
48. Dietz, R. N.; Cote, E. A.; Smith, J. D., New method for calibration of permeation wafer and diffusion devices. Analytical Chemistry 1974, 46, 2, 315-318.
49. Moosbach, E.; Hartkamp, H., Influence of carrier gas pressure on permeation rates of the “Hartmann & Braun CGP”-NO2-test gas generator. Fresenius'' Journal of Analytical Chemistry 1993, 347, 12, 475-477.
50. Talbot, R. W.; Dibb, J. E.; Lefer, B. L.; Scheuer, E. M.; Bradshaw, J. D.; Sandholm, S. T.; Smyth, S.; Blake, D. R.; Blake, N. J.; Sachse, G. W.; Collins, J. E.; Gregory, G. L., Large-scale distributions of tropospheric nitric, formic, and acetic acids over the western Pacific basin during wintertime. J. Geophys. Res. 1997, 102, D23, 28303-28313.
51. Jost, C., Calibration with permeation devices: is there a pressure dependence of the permeation rates? Atmospheric Environment 2004, 38, 21, 3535-3538.
52. Washenfelder, R. A.; Roehl, C. M.; McKinney, K. A.; Julian, R. R.; Wennberg, P. O., A compact, lightweight gas standards generator for permeation tubes. Review of Scientific Instruments 2003, 74, 6, 3151-3154.
53. Wang, J.-L.; Chew, C.; Chen, S.-W.; Kuo, S.-R., Concentration variability of anthropogenic halocarbons and applications as internal reference in volatile organic compound measurements. Environmental Science & Technology 2000, 34, 11, 2243-2248.
54. Karbiwnyk, C. M.; Mills, C. S.; Helmig, D.; Birks, J. W., Use of chlorofluorocarbons as internal standards for the measurement of atmospheric non-methane volatile organic compounds sampled onto solid adsorbent cartridges. Environmental Science & Technology 2003, 37, 5, 1002-1007.
55. http://www.noaa.gov/
56. Helmig, D., Balsley, Ben , Birks, John , Karbiwnyk, Christine , Mills, Craig, , Analytical and Monitoring Methods (1996) : Measurements of non-methane volatile organic compounds in the lower troposphere from tethered balloon and kite sampling platforms by internal standard calibration using ambient CFC reference compounds. EPA: 1996.
57. Wang, C.-H.; Chiang, S.-W.; Wang, J.-L., Simultaneous analysis of atmospheric halocarbons and non-methane hydrocarbons using two-dimensional gas chromatography. Journal of Chromatography A 2010, 1217, 3, 353-358.
58. 廖千宜, 多孔材料吸附特性研究與氣體線上校正方法探討. 中央大學化學研究所: 2009.
59. Tumbiolo, S.; Vincent, L.; Gal, J.-F.; Maria, P.-C., Thermogravimetric calibration of permeation tubes used for the preparation of gas standards for air pollution analysis. The Analyst 2005, 130, 10, 1369-1374.
60. Sanchez, J. M.; Sacks, R. D., On-line multibed sorption trap and injector for the GC analysis of organic vapors in large-volume air samples. Analytical Chemistry 2003, 75, 4, 978-985.
61. http://www.sigmaaldrich.com/australia.html.
62. 王介亨, 以Heart-cut技術配合單偵檢器發展氣相層析“剪裁(tailoring)”技術. 中央大學化學研究所: 2004.
63. Slemr, J.; Slemr, F.; D''Souza, H.; Partridge, R., Study of the relative response factors of various gas chromatograph-flame ionisation detector systems for measurement of C2-C9 hydrocarbons in air. Journal of Chromatography A 2004, 1061, 1, 75-84.